What happens when your SmarterMail Enterprise server gets out of sync with Plesk? Among other things, Plesk gets fussy. I swear, just a few days ago I could add and remove mailboxes just fine. Today I spend some time figuring out how to make Plesk and SmarterMail play nice again.
mchk.exe --domain --domain-name=mydomain.com
It's a Plesk command line tool that makes Plesk see SmarterMail at a "special" level. Yes, it works. It doesn't sync up mail accounts, but I just needed to delete the domain anyway. This did the trick.
The tool itself has a bite, be careful with it.
http://download1.swsoft.com/Plesk/Plesk7.5/Windows/Docs/plesk-7.5-win-advanced-features-manual/9781.htm
http://www.swsoft.com/
http://www.smartertools.com/ -- corporate e-mail -- customizable, stables, I love it!